This invention relates to an activated gas reaction apparatus and more particularly to apparatus employing gas activated by microwave power.
Recently in the field of semiconductor manufacturing, there has been developed an apparatus designed to activate gas by radio frequency (RF) discharge, and carry out the ashing of a photoresist or the etching of, for example, a silicon layer. Ashing or etching of a film is supposed to proceed by radical reaction between the film and activated gas.
With the above-mentioned apparatus, an activation chamber in which feed gas is activated by RF discharge is generally concurrently used as a reaction chamber in which a chemical reaction such as ashing takes place. Further, activation of a reaction gas has been effected by RF power of 13.5 MHz and at a pressure lower than 1 torr. Such apparatus has the drawback that the ashing of, for example, a photoresist, consumes a great deal of time, because the RF discharge is carried out at low pressure and low power density. Further disadvantages of the prior art apparatus are that a pressure higher than 1 torr results in unstable RF discharge; high power density is unavailable; and power efficiency is low.